Association Between Obesity and Blood Pressure Among Iranian Children and Adolescents: A Sub-analysis from the SHED LIGHT Study

Reference percentiles for tri-ponderal mass index and its association with general and abdominal obesity among Iranian children and adolescents: A report from the SHED LIGHT study

BACKGROUND

The body mass index (BMI) has some limitations in identifying obesity, particularly among children and adolescents.

OBJECTIVES

We sought to determine the reference percentiles of tri-ponderal mass index (TMI) for Iranian population, and its relation to BMI, waist circumference (WC), and waist circumference-to-height ratio (WHtR).

METHODS

Baseline characteristics for 14 641 children and adolescents were applied. The area under the characteristics (AUC) curve and optimal cut-off points for TMI were used to define the accuracy of TMI for discriminating general and central obesity compared to other anthropometric measurements.

RESULTS

TMI levels remained stable from 6 to 18 years with a small range of difference. The highest AUCs for discriminating obesity according to BMI and WHtR ≥0.5 from non-obese subjects were related to TMI (0.980) and TMI (0.912), respectively, and these findings were similar for both sexes. Moreover, the AUC for TMI to discriminate central obesity by WHtR was higher than that for BMI (0.912 vs. 0.833, p < .001), and this difference was similar among sex and age groups. The optimal value of TMI for discriminating general obesity, obesity by WC, and obesity by WHtR were 15.2 (sensitivity 96.2 and specificity 89.8), 15 (sensitivity 86.9 and specificity 79.9), and 13.9 (sensitivity 85.1 and specificity 81.5), respectively.

CONCLUSIONS

TMI discriminated central obesity by WHtR more accurately than obesity by BMI among Iranian children and adolescents irrespective of sex. Besides it remained relatively constant across age- and sex-specific groups providing a single optimal cut-off point for screening obesity during childhood and adolescence.

Waist-to-height-ratio is associated with sustained hypertension in children and adolescents with high office blood pressure

Background

Waist-to-height-ratio (WHtR) has been proposed as another indicator for cardiometabolic risk factors including hypertension. Normally, hypertension can be diagnosed in the office setting by detecting high blood pressure for three occasions. However, patients with high office blood pressure may not exhibit high blood pressure outside the office. Ambulatory blood pressure monitoring (ABPM) is a procedure to measure blood pressure over 24-h. Sustained hypertension is characterized as hypertension detected by both office measurement and ABPM. This study aimed to evaluate the performance of WHtR in the diagnosis of sustained hypertension in patients with high office blood pressure.

Materials and methods

Demographic data, height, body weight, body mass index (BMI), and waist circumference were retrospectively reviewed in children and adolescents who underwent ABPM due to persistently high office blood pressure. Patients were separated into two groups: a sustained hypertension group and a normal ABPM group. BMI was adjusted to z-score using the WHO Anthroplus software. WHtR was calculated by the formula: waist circumference (cm)/height (m). The performances of different parameters were analyzed using the receiver operating characteristic (ROC) curve and multivariate logistic regression.

Results

Sixty patients (63% male) with a mean age of 12.9 ± 3.7 years had persistently high office blood pressure. Twenty-nine (48.3%) had high ambulatory blood pressure parameters so-called "sustained hypertension." The sustained hypertension group had a higher mean BMI z-score (2.32 vs. 1.31, p = 0.01) and a higher mean WHtR (57.7 vs. 49.2 cm/m, p < 0.001) than those of the normal ABPM group. For the diagnosis of sustained hypertension, the ROC analysis revealed that WHtR had a greater area under the ROC curve (AUC) than that of BMI z-score (0.772 vs. 0.723). WHtR remained associated with sustained hypertension (OR 1.2, 95% CI 1.022-1.408, p = 0.026) after adjusting for age, gender, and BMI z-score.

Conclusions

Apart from being a more user-friendly metric, WHtR tended to outperform BMI z-score in predicting sustained hypertension in children and adolescents with persistently high office blood pressure.

FUNCTIONAL CHARACTERISTICS OF THE CARDIOVASCULAR SYSTEM OF PATIENTS WITH ISCHEMIC HEART DISEASE WITH OBESITY

OBJECTIVE

The aim: To determine the features of the functional characteristics of the cardiovascular system of patients with ischemic heart disease with obesity.

PATIENTS AND METHODS

Materials and methods: Examined 130 persons (mostly military personnel and persons who were in the zone of active hostilities): 65 patients (the main group, 62,67±8,93 years) with coronary heart disease and obesity and 45 people of the control group (virtually healthy people, randomized by age and sex, 58,76±14,6 years).

RESULTS

Results: Coronary heart disease and obesity compared to healthy individuals probably the exceed all values of the functional state of the cardiovascular system: systolic blood pressure (152.72±14.61 and 119.03±7.94 mmHg; p<0.001); diastolic blood pressure (90.74±7.36 and 80.36±6.74 mmHg; p<0.001); end-diastolic volume (103.17±40.84 and 52.48±8.58 mm3; р<0.001); end-systolic volume (47.98±29.92 and 31.47±8.42 mm3; р=0.001); end-diastolic size (4.74±0.81 and 4.12 ± 0.27 cm; р<0.001); end-systolic size (3.34±0.76 and 3.17±0.59 cm; р=0.014).

CONCLUSION

Conclusions: The identified functional disorders of the heart in the comorbid course of coronary heart disease and obesity can be used for early diagnosis of cardiovascular complications in such patients and for the development of adequate therapeutic schemes.